The Wide band Code Division Multiple Access (WCDMA) is a kind of 3rd generation wireless communication systems, and its air interface uses a method of code division multiplexing to perform a broadband spread spectrum wireless communication and provide data transmission services to an upper layer.
In the air interface of the WCDMA, a carrier bandwidth is 5 MHz (megahertz), the frequency bands are used in pairs, namely, one for uplink, and the other for downlink. The air interface of the traditional WCDMA only uses a pair of frequency bands (one carrier for uplink, and one carrier for downlink), to transfer the data between a terminal and a node B. For the next technique development trend of the WCDMA, a multi-carrier high-speed downlink packet access technique has very obvious and unique advantages. On this basis, a Multiple-Input Multiple-Output (MIMO) technique is also applied rapidly. The MIMO can improve the capacity of the channel, and improves the reliability of the channel and reduces the bit error rate at the same time; the former is due to a utilization of a spatial multiplexing gain provided by the MIMO channel, and the latter is due to a utilization of a space diversity gain provided by the MIMO channel. For the MIMO system, multipath is utilized as a favorable factor. The MIMO system adopts multi-antenna (or array antenna) and multi-channel on both the transmitting end and the receiving end, and the multi-input multi-output of the MIMO is for the multipath wireless channel. The transmitted information flow forms a plurality of information sub-flows through space-time coding. This plurality of information sub-flows are launched out by a plurality of antennas, and received by a plurality of receiving antennas after passing through the space channel. The multi-antenna receiver can separate and decode these data sub-flows by utilizing the advanced space-time coding processing, thus realizing the optimal processing.
In one cell, a common pilot channel can be used to estimate the channels seen from different antennas respectively. Wherein, an antenna sends a primary common pilot channel with a modulation mode of “antenna mode one”; and another antenna can send the primary common pilot channel with a modulation mode of “antenna mode two”, and also can send a secondary common pilot channel with the modulation mode of “antenna mode one”.
Such a MIMO pilot frequency configuration mode that an antenna sends the primary common pilot channel with the modulation mode of “antenna mode one”, and, another antenna sends the secondary common pilot channel with the modulation mode of “antenna mode one” is called a MIMO pilot mode of the “primary and secondary common pilot channel”.
In the MIMO pilot mode of the “primary and secondary common pilot channel”, the secondary common pilot channel provides information of the phase difference of the second transmitting antenna of the MIMO. A ratio of the transmission power of the primary common pilot channel to the transmission power of the secondary common pilot channel is called “power offset of the secondary common pilot channel operated for the MIMO”. The nominal unit of the “power offset of the secondary common pilot channel operated for the MIMO” is Decibel (dB), of which the range is usually between −6 and 0. When the “power offset of the secondary common pilot channel operated for the MIMO” is 0, it just means that there is no power offset of the transmission power of the secondary common pilot channel relative to the transmission power of the primary common pilot channel, and the transmission power of the secondary common pilot channel equals to the transmission power of the primary common pilot channel.
In order to state concisely, the “power offset of the secondary common pilot channel operated for the MIMO” is abbreviated as the power offset of the secondary common pilot channel. The expression approach of the power offset of the secondary common pilot channel will be used hereinafter.
One cell has one and only one carrier, when a single carrier high-speed downlink packet access technique is used, the cell where the single carrier locates and which performs the data transmission by using the high-speed downlink packet access technique is called a single carrier cell. When the multi-carrier high-speed downlink packet access technique is used, at least 2 cells which use the high-speed downlink packet access technique to perform the data transmission must be required, wherein, the carrier of one cell is a primary carrier, and the carrier of another cell is a secondary carrier. The cell where the primary carrier locates and which uses the high-speed downlink packet access technique to perform the data transmission is called the primary carrier cell; and the cell where the secondary carrier locates and which uses the high-speed downlink packet access technique to perform the data transmission is called the secondary carrier cell.
When the multi-carrier high-speed downlink packet access technique is used, the primary carrier cell and the secondary carrier cell can use the MIMO separately in the downlink direction. For example, the primary carrier cell can use the MIMO pilot mode of “the primary and secondary common pilot channels” in the downlink direction; each secondary cell can also use MIMO pilot mode of “the primary and secondary common pilot channels” in the downlink direction. Utilization of the MIMO of each primary and secondary carrier cells other is independent with each other, and there is no restrained relationship. In the MIMO pilot mode of “the primary and secondary common pilot channels”, the ratio of the transmission power of the primary common pilot channel to the transmission power of the secondary common pilot channel of this cell needs to be transmitted, so as to enable the terminal to decode and receive the high-speed downlink packet access data in the downlink direction of the cell.
An IUR (Interconnection of RNC, the interconnection interface between the radio network controls) is an interface used by a radio network control to perform the signaling and data interaction with other radio network controls, it is a bond of the interconnection between the wireless network subsystems.
When a terminal establishes a connection from the terminal to a wireless access network, and produces a soft handover on an IUR interface, then the resources of more than one radio network controls will be used; different radio network controls serve as different roles at this moment:                a Serving Radio Network Control (SRNC). A radio network control that keeps the interface connection of the terminal and the core network is the serving radio network control. The serving radio network control is responsible for the data transmission between the core network and the terminal, and the transmission and receiving of the interface signaling of the core network, responsible for performing the wireless resource controlling, and responsible for performing the processing of layer two for the data of the air interface, and executing the basic management operations of the radio resources, such as, a handover decision, an external loop power control, and a transformation from parameters born by a radio access to parameters of an air interface transmission channel, etc.        a Drift Radio Network Control (DRNC). A drift radio network control is another kind of radio network control except the serving radio network control. The drift radio network control controls a cell used by the terminal; if necessary, the drift radio network control can perform a macro-diversity combination. Unless the terminal uses a common transmission channel, the drift radio network control will not perform the layer two processing of the data on the terminal plane, while it only transparently transmits the air interface data to the serving radio network control through a route of the IUR interface. The drift radio network control of one terminal can be of more than one.        
When the terminal prepares to move across the IUR interface (such as, the handover, serving cell changing, etc.), to hand over from source primary and secondary carrier cells managed by the serving radio network control to target primary and secondary carrier cells managed by the drift radio network control, the serving radio network control needs to request the drift radio network control through the IUR interface to feed back the power offset information of respective secondary common pilot channels of the target primary and secondary carrier cells managed by the drift radio network control to the serving radio network control. The serving radio network control informs the terminal of the power offset information of respective secondary common pilot channels of the target primary and secondary carrier cells managed by the drift radio network control through the air interface, and then the terminal can only correctly access and use the resources of the target primary and secondary carrier cells managed by the drift radio network control.
However, the inventor of the application of the present document finds in practice that: in real application, during the process of “the serving radio network control needs to request the drift radio network control through the IUR interface to feed back the power offset information of respective secondary common pilot channels of the target primary and secondary carrier cells managed by the drift radio network control to the serving radio network control”, a phenomenon will appear that part of the serving radio network controls are unable to resolve the power offset information of respective secondary common pilot channels of the target primary and secondary carrier cells all the time.